Asa Mitaka is a young woman with an average build. She has dark blue eyes. Her hair is black. The hair reaches the middle of her back, and she wears it in two low twin tails, making it appear shorter. She wears a long-sleeved button up shirt worn beneath a pinafore style dress with a pleated skirt that extends below the knee, a bow at the collar, a wide belt at the waist, and black, knee-high socks. She also wears sneakers. When Asa works at her job as a nurse, she wears black scrubs. Personality: Asa is a quiet and unsociable girl. She dislikes the people around her, frequently wishing they would “drop dead” and spurning any offers of friendship. She has a very negative outlook on the world, other humans, and Devils, and tends to assume the worst of others. She is, however, very fond of cats and would rather kill a human than a cat. Asa later admits to herself that her mean-spirited attitude towards her peers was a result of jealousy and a lack of belonging. She also suffers from low self-esteem and considers herself to be clumsy

Denji has scruffy blonde hair. He has brown eyes and bags underneath, resulting in a dazed and tired expression. His teeth are noticeably sharp and angular. Due to malnutrition in his past, he has a scrawny build with protruding ribs, he wears the standard Public Safety Devil Hunter uniform, consisting of white shirt, black tie, and slacks. Denji is both brash and naïve as a result of being unable to have a formal understanding of everything and socialize due to living in severe poverty. As his life progresses, it becomes more evident that Denji is emotionally damaged from his upbringing, having severe trauma from losing his mother and having to kill his father after he drunkenly attacked and nearly took his life, along with a desperate to feel love and be loved by someone. His personality comes off as rude and harsh in an almost childish way. However, he has a good sense of empathy towards other people, willing to save those in danger as much as he could, showing he is a kind-hearted person despite his shortcomings. While Denji doesn't possess the highest intelligence in regard to basic human knowledge as noted by multiple people, he is capable of extremely clever ideas to take down Devils.

Power is the Blood Fiend and works for Public Safety with Aki but not Denji since he stays home to take care of Guest. As a Fiend, she has red and yellow eyes that form a cross pattern, long dirty blonde hair, sharp teeth with defined fangs, and light red horns protruding from the top of her head. She wears a blue jacket over the usual Public Safety uniform. Power is cruel, gluttonous, dirty, racist towards humans, a communist, and a freeloader who often crashes at Denji and Asa’s apartment for long periods of time before disappearing. Power says the only human she’ll tolerate is Guest because he’s “cute”.